An inspection or a test of a packaged or molded semiconductor device, and more particularly, of an integrated circuit (IC), is generally conducted by using an electrical connecting apparatus such as an inspection socket, that is, a test socket which can mount a semiconductor device removably as an auxiliary means for inspection.
As a type of such an electrical connecting apparatus, can be given one that tests a semiconductor device by a Kelvin connection which improves the accuracy in measurement by canceling circuit resistance within the electrical connecting apparatus or an apparatus for electrical test as well as contact resistance and the like between a contact, a conductive portion and a lead electrode (Japanese Patent Appln. Public Disclosure No. 3-176676 Official Gazette), and one that uses a plurality of contacts curved substantially like a shape of J (Japanese Patent Appln. Public Disclosure No. 2003-123874 Official Gazette).
In the former apparatus, each contact uses a pair of contact pieces (socket leads) having a first and a second contact portions (lead portions), and each second contact portion, when inserted into a corresponding hole of a base plate such as a wiring base plate, is brought into contact with a corresponding conductive portion of the base plate.
In the former apparatus, however, both contact pieces of each contact are independent from each other, making it difficult to correctly position one contact piece relative to the other contact piece and an adjacent contact piece when exchanging the contact pieces. Therefore, it is troublesome to exchange the contact pieces.
In the latter apparatus, each contact has a sandwich-type three-layer structure with a substantially J-shaped thin electrical insulator interposed between a pair of plate-like contact pieces. The contacts are arranged in parallel at intervals in one direction in a cover, with their needle points inserted into a slit formed in the cover, and with the cover assembled into the base plate, the curved portion of a stick-like elastic body such as rubber disposed in the cover is pressed against the corresponding conductive portion of the base plate.
In the latter apparatus, however, the cover must be separated from the base plate when exchanging the contacts. Such separation releases pressing of all the contacts by the elastic body against the conductive portion of the base plate, so that many contacts cannot be prevented from falling off the cover. Consequently, when reassembling the cover into the base plate, the contacts which have fallen off should be rearranged in the cover in parallel at intervals in one direction. Therefore, it is troublesome to exchange the contacts.